|Environmental Factors – A scale’s accuracy and precision are highly dependent on the environment in which it is installed. Several environmental factors can affect the scales measurement including:
Zero Error – Occurs when the weighing curve shifts by a constant amount. For the most part, you can avoid this error by using the re-zero function before performing a weighing.
Sensitivity Error – Quotient of the change in an indication of a measuring system and the corresponding change in a value of a quantity being measured. Sensitivity of a measuring system can depend on the value of a quantity being measured increasing linearly with heavier loads. Sensitivity errors can occur from temperature drift, aging, adjusting with an incorrect calibration weight, or incorrect compensation of an off-center load error.
Linearity – This is the ability of a scale’s characteristic curve to approximate a straight line. Linearity can be tested by weighing several test weights of increasing value up to maximum capacity and plotting them as points in a graph. The linearity would be the maximum amount that the points deviate from a straight line going from zero to max capacity.
Random Error – The sample standard deviation of the error (indicated values) for a number of consecutive automatic weighings of a load, or loads, passed over the load receptor, shall be expressed mathematically as: